Intrathecal administration

Subarachnoid space
Diagrammatic representation of a section across the top of the skull, showing the membranes of the brain, etc. ("Subarachnoid cavity" visible at left.)
Diagrammatic transverse section of the medulla spinalis and its membranes. (Subarachnoid cavity colored blue.)
Details
Identifiers
Latin	Spatium subarachnoideum, cavum subarachnoideale
Anatomical terminology [edit on Wikidata]

Intrathecal administration is a route of administration for drugs via an injection into the spinal canal, or into the subarachnoid space so that it reaches the cerebrospinal fluid (CSF). It is useful in several applications, such as for spinal anesthesia, chemotherapy, or pain management. This route is also used to introduce drugs that fight certain infections, particularly post-neurosurgical. Typically, the drug is given this way to avoid being stopped by the blood–brain barrier, as it may not be able to pass into the brain when given orally. Drugs given by the intrathecal route often have to be compounded specially by a pharmacist or technician because they cannot contain any preservative or other potentially harmful inactive ingredients that are sometimes found in standard injectable drug preparations.

Intrathecal pseudodelivery is a technique where the drug is encapsulated in a porous capsule that is placed in communication with the cerebrospinal CSF. In this method, the drug is not released into the CSF. Instead, the CSF is in communication with the capsule through its porous walls, allowing the drug to interact with its target within the capsule itself. This allows for localized treatment while avoiding systemic distribution of the drug, potentially reducing side effects and enhancing the therapeutic efficacy for conditions affecting the central nervous system.

The route of administration is sometimes simply referred to as "intrathecal"; however, the term is also an adjective that refers to something occurring in or introduced into the anatomic space or potential space inside a sheath, most commonly the arachnoid membrane of the brain or spinal cord^[1] (under which is the subarachnoid space). For example, intrathecal immunoglobulin production is production of antibodies in the spinal cord.^[2] The abbreviation "IT" is best not used; instead, "intrathecal" is spelled out to avoid medical mistakes.^{[citation needed]}